Bonus Content

Any slip-up, however, can mean a unpleasant call from your milk handler and a potential visit from your state department of agriculture. Avoiding residues takes constant vigilance and attention to detail, says Norbert Nigon, a veterinarian with the Minnesota Department of Agriculture’s Dairy and Feed Inspection Division.

"Continuing to rely on testing cows that are known to have been treated will only keep milk residues at current levels," he says. "Most violations are caused by treated cows that had no identifying information at the time of milking to indicate that their milk was to be withheld from the bulk tank."

Follow-up visits to Minnesota farms with reports of residues in milk show that 95% of residues were caused by milking a treated cow or dry cow by mistake. And only one in seven farms tested the bulk tank before loading the milk onto a tanker or had written treatment protocols from their veterinarians.

There are seven simple steps to reduce the potential for residues, Nigon says:

1. Keep detailed animal treatment records for at least two years. Records should include cow ID, date and time (a.m. or p.m.); diagnosis, drug used, amount of drug given, route of administration (intermuscular, subcutaneous, IV or intramammary) and initials of person giving the drug.